Wireless-telephone transmitting system.



L. DE FOREST.

WIRELESS TELEPHONE TRANSMITTING SYSTEM.

APPLICATION FILED SEPT. 17, 1910. 1 [125,496 Patented Jan. 19,1915.

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mm--- mm H Amm L. DE FOREST. WIRELESS TELEPHONE TRANSMITTING SYSTEM. APPLICATION FILED SEPT. 1'7, 1910.

1,125,496., Patented Jan.19,1915.

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UNITED STATES PATENT ornion.

LEE DE ronnsr, or NEW YORK, N. in, ASSIGNOB, TO RADIO TELEPHONE &- TELEGRAPH COMPANY, A GORIORATION OF DELAWARE.

WIRELESS-TELEPHONE TRANSMITTING SYSTEM.

Specification of Letters Patent.

Patented ran. 19, was.

Application filed September 17, 1910. Serial No. 582,449.

To all 1071 om it may concern:

Be it kno n that I, LEE or. Fonns'r, a

phone transmitting systems.

The object of the invention is to provide a wireless telephone transmitting systemv throw the high frequency oscillations -of the antenna and primary .oscillating cirhereinaftm' set forth, as shown in the achigh frequency oscillations.

cuits more or less out of tune witlpeach other.

A further object is to provide a system of the nature referredto wherein the rela-' tive inductance of the antenna and primary oscillating circuits is variedin the transmission of'speech.

A further object is to provide a system of wireless telephony employin a radiotone or quenched spark system 0 excitation of A further object is to provide a system of wireless telephony employing slowly damped radiated waves.

Other objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, arrangement, and relative location of parts all as will be more fully companying drawings and finally pointed out in the appended claims.

In the drawings,Figure liis a view in diagram showing a circuit arrangement in a system embodying my invention, and

wherein the telephone transmitter is ar-' ranged to more 01' less short circuit part of the inductance in the high frequency circuit of theantenna system, as, for instance a coil of the coupling system. Fig. 2 is a similar view wherein the telephone transmitter is arranged to short circuit more or less of an extension of a coil in the antenna coupling system. .Fig. 3 is a similar View wherein the telephone transmitter is associated 1nductively with a coil of the ,coupling system.

Fig. 5 is a similar view wherein the telephone transmitter is associated with an extra inductance coil in. primary high frequency oscillating circuit. detail diagrammatic view ofa microphone or telephone transmitter circuit suitable for use in connection with my invention. Fig. 7 is a view in'diagram showing a quenched or series spark gap and with the microphone connected across a portion of said p I In carrying out my invention-I propose to cmploy'a source of alternating or interrupted current having a freuency of alterna tion or interruption within the upper limit of audibility and yet, sufficiently high to revent the hum thereof from unduly intererin with voice transmission. I have foun a source of alternating current having a frequency within the upper limit of my purposes. From this source of alternat- Fig. 4 is a similar-view: wherein the telephone transmitter is -ass o-"" ciated directly in the antenna earthclrcuit.

Fig. 6 is a ing or interrupted current, and when I hereinafter refer to alternating current I wish also to include thereby interrupted current, I pro ose to excite high frequency oscillations o generating electro-magnetic radiation for space communication. I have found that the radiotone system of excitation well answers my purpose; that is, a system of shock excitation such as is accomplished by the quenched spark or singing spark the character required for v method, although in this respect my invention as defined in the claims is not to be limited or restricted. The radiotone system, however, possesses the advantage of effecting the radiation of slowly damped waves which are particularly suitable for my purposes. I also propose, in accordance with the principles of my invention, to associate the microphone or other telephone transmitting device with a high frequency circuit ofthe system. This associationwith coils of-the high frequency helix. This may 4 be "(a coil of the coupling system, thereby varying the inductance of the antenna system. This short 'circuiting arrangement of the microphone may be accomplished with reference to an extension of such high. frequency helix or coupling coil, or the microphone circuit may be inductively associated with some convenient. part of a hi h frequency circuit, as, for instance, with the high frequency helix or coupling'coil; or it may be associated with an-extra coil in the primary oscillating circuit, or it maybe located directly-in the antenna earth circuit,

' although generally, in this latter case the power employed should be comparatively small otherwise the current through, and the s arking in, the microphone, might tend to in ure the same. In all cases the microphone, inaccordance with my invention, should be associated with some part of a high frequency circuit, having the characteristics above pointed out, and the association should be such that variations of resistance in the microphone circuit due to sound vibrations impinging on the diaphragm of the microphone, cause corresponding variations in the inductance of the high frequency 'circuit with which the microphone is associated, the high frequency oscillations being excited by an alternating or interrupted current having a frequency below the u per audible limit, and above, say, four [cycles per second. These variations cause [the antenna and primary high frequency oscillating circuits to be thrown more or less ut of tune with each other,'there by corre spondingly modifying the slowly damped radiated Waves.

1- g gihploying theradiotone, quenched or s'i n spark. system of excitation of the aps are used in series in the primary high equency oscillating circuit, thereby attaining ,a quick quenching of' each spa'rk .dis-. charge and a'resultin'g shock excitation,

'. the radiation of slowly damped waves;

Referring to Fig. 1, A designates theiantenna, E its earth connection, and B an alternating or interrupted current "source, such for instance, as an alternating current gener'-' ator of a frequency of at least four hundred is connected with the' oscillating circuit in cycles per second. The current source B "suitablemanner, as through a step-up trans 'former F.v The-oscillating circuit, contains the usual capacity, as condenser C, and in-i ductanc'eym series, and has thetqdischarger For instance, the

quenched, the air gaps or spaces between undred equency oscillations, a plurality ofr uency oscillating cir ifig th multiple spark gap D, connected across said circuit. The oscillating circuit may be associated with the antenna system in any suitable and well known manner. I'h'ave ,shown' an adjustable conductive coupling for this purpose. In a generating and radi 1 ating system such as above described the oscillations in the antenna system are shock excited, each spark discharge being quickly the plates or disks constituting and forming the spark gap structure enabling this'result to be accomplished, and b reason of the quick quenching of the spariifollowing eachdischarge, and the .high resistance resulting from the multiple gaps in the dis charger, there isno reflex action from the antenna system back into the primary oscillating circuit; The result is the radiation of slowly damped waves having an intensity and capable of carrying the radiationsthrough extended distances and, by. reason of the modifications imposed thereon by the sound waves impinging upon the telephone transmitter or microphone associated with one of the high frequency circuits ofthe system, .capableof being utilized for the transmission of articulate speech. In Fig. 1 the modifications of the radiatedwaves, by and in accordance with'sou'n'd waves, isaccomplished by associating the microphone or telephonevtransmitter M with the coupling coil or high frequency helix ,G constituting part of the conductive coupling between the antenna system and the primary high frequency oscillating system, in such relation as to more or less short circuit part of such helix or coil, thereby enabling changes in the resistance in the telephone transmitter or microphone due to sound waves impinging upon the diaphragm thereof to effect a variation'in the inductance of the antenna system. In Fig.. 2 I have shown the' microphone or'telephone transmitter 'M associated with an extension H of the coil G in such relation and adjustable connection therewith as to short circuit more or less of suchegztension, thereby providing mean's for modify ing the inductance of a high frequency ea cuit by and in accordance with: the sound waves accompanying articulate speech.

k In Fig. I have shown the microphone or telephone transmitter M associated inducti'velywith coil G.

In Fig. 4 I have s own the microphone .Mlocated directly in he antenna earth circuit. When this arrangement is employed, however, the power used should be small order to prevent the current and sparking in the microphone from injuring or destroying suchmicrop'hone. In Fig. 5 I have shown an extra indu'ctance or coil J in the primary hi phone M being shunted around and adjustcircuit L of the microphone M may contain a condenser C.

The radiated waves modified by or in accordance with 'the sound waves accompanying articulate speech, in the manner above set forth may be received at a receiving station by any suitable or well known arrangement of wireless receivin system, and'the oscillations generated in t e receiv ing system by the modified waves, utilized for reproducing or in reproduction of the sound waves employed to effect the initial modifications.

While I have shown and described various arrangements embodying my invention, and various manners of association of the microphone or telephone transmitter with a high frequency circuit, or portion thereof supplied from analternating or interrupted current source, my invention, as defined in the claims, and in their broadest scope, is not to be limited or restricted to the exact arrangement shown. a

Fig. 7 shows an arrangement by which the microphone acts to more or less short circuit a portion of the series spark gaps. I find that if four gaps in series be em ployed it is satisfactory to connect the microphone across two of these gaps. But v Having now set forth the object and nature of my invention and various constructions embodying the principle thereof, what I claim as new and useful and of in own invention and desire to secure by Patent is,

1. A wireless telephone transmitting system, including a source of alternating current supply having a frequency below the upper audible limit, and a multiple spark .gap, and means for modifying the radiated Waves from such system by and in accordance with sound waves. a

2. wireless telephone transmitting system including a source of alternating current supply to a quenched spark gap, the alternating current having a frequency below the upper audible limit, in combination with means for modifying the generated oscillations by and in accordance with sound waves.

v 3. In a wireless telephone transmitting system, an oscillating circuit including a quenched spark gap, an antenna circuit associated with said oscillating circuit, and a source of alternating current supply for said etters' oscillating circuit, in combination with a telephone transmitting device associated with one of said circuits and arranged to vary the inductance thereof by and in accordance with sound .Waves.

4. In a wireless telephone transmitting system, an oscillating circuit including a quenchedspark gap, an antenna circuit associated with the oscillating circuit, and a source of current supply for the oscillating circuit, incombination with means .for modifying the generated oscillations by and in accordance with sound waves and including means for varying the inductance in one tem, having means for radiating slowly damped waves of audible group frequency,

and means for modifying the radiated waves by and in accordance with sound v1- .brations.

7. A wireless telephone transmitting system for radiating slowly damped waves of audible group frequency and including a high frequency circuit, and a telephone transmitter device associated with said c1rcuit to modify the oscillations therein by and-in accordance with sound Vibrationsfi 8 A wireless telephone transmitting system for radiating slowly damped waves at audible group frequency and 1ncl ud1ng a high frequency circuit, in combinatlon with a telephone transmitter device arranged to vary the inductance of said high frequency circuit by and in accordance with sound vibrations.

In testimony whereof I have hereunto set my hand in the presence of the subscribing witnesses, on this 9th day of September A. D, 1910.

' 1 LEE DE FOREST.

Witnesses:

CLARENCE Humcxn, MAE W. CLIN'roN.

v Disclaimer in Letters Patent No. {T2549 6Q -Enters this disolaimer, o "(To that' pai't of the claim -insaid specification, being claims 1, 2, 6; and'T, which is in thefollowing words; to wit: t Y

iii-96:81:66 Foresti New Y 01113 wIRnLnss El flofin TRANSMI T l Q; Disclaimerfiled g smm- Patent dated January 19, 1915.

" the lassig n ee, De ForestRad'io 'Tele'phone da Telegraph 00.

. 1. A Wireless telephone transmitting system, including a souroe of talternatiin g" currentsupply having a frequency below the upper audi 1e hmitfand. a multiple spark ga and means for modifying the radiated waves in aocor ance with sound waves.

current 'supply to a quenched the alternating-currenthaving a fre-.

spark gap qfile'noy below the upper audib t e generated oscillations by and in aeoordance'withsound waves.

hone transmitting system, havmg-means {0 36. 'A Wireless tele for modifying the radiated damped waves of au lble group frequency, andmean's Waves'by'and in acoordanoe with sound vibrations. .7. A wireless telephone transmitting s tem wavesfof audible group frequency and mo uding P a telephone transmitter devlce asso'eiated with said Iations therein by and in accordance sound vibrationsP-f v a highfrequenoy oircu t, and

circuit to modify the; oscilf 0 7 z Gazette, May 9, 191 .1

fromsuch system lay and 2. Awireless telephone transmitting system including a source of alternating le hmit, in combination with means for modifying radiating slo di timing ,slowly iaepea 

